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            <h2 class="title" style="clear: both"><a id="upgrade_4_8_mpool"></a>Minor Change in Behavior of DB_MPOOLFILE-&gt;get</h2>
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      <p>
    DB 4.8 introduces some performance enhancements, based on the use
    of shared/exclusive latches instead of locks in some areas of the
    internal buffer management code. This change will affect how the
    <code class="classname">DB_MPOOL</code> interface handles dirty buffers.
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      <p> Because of these
    changes, <code class="methodname">DB_MPOOLFILE-&gt;get</code> will now
    acquire an exclusive latch on the buffer if
    the <code class="literal">DB_MPOOL_DIRTY</code>
    or <code class="literal">DB_MPOOL_EDIT</code> flags are specified. This
    could lead to an application deadlock if the application tries to
    fetch the buffer again, without an
    intervening <code class="methodname">DB_MPOOLFILE-&gt;put</code> call.
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      <p>
    If your application uses the <code class="literal">DB_MPOOL</code>
    interface, and especially the <code class="literal">DB_MPOOL_DIRTY</code>
    and <code class="literal">DB_MPOOL_EDIT</code> flags, you should review your
    code to ensure that this behavior change does not cause your
    application to deadlock.
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